Homocysteine is a sulfur-containing amino acid and a metabolite of methionine metabolism. Recent clinical studies have strongly suggested that an elevated level of homocysteine in blood is a risk factor for cerebrovascular, peripheral vascular and coronary heart diseases. However, the exact role that homocysteine plays in these diseases. is not well understood. In addition the prognostic value of plasma homocysteine concentrations for cardiovascular diseases has not yet been validated. In order to expedite the ongoing effort to better understand the role that homocysteine and other endogenous sulfhydryls and disulfides play in cardiovascular diseases, the development of a simple, reliable, high throughput and cost effective assay for the determination of homocysteine and other biological important thiols in plasma is essential. The objective of the proposed work is the development of a fast, sensitive and selective clinical assay for the determination of homocysteine and other endogenous thiols and disulfides in plasma. This will be accomplished using capillary electrophoresis with electrochemical detection. This assay should offer attractive features such as simpler sample processing (since native thiols are detected), high sensitivity, specificity, portability and the possibility of high sample throughput. The resulting methodology will provide clinical scientists with a simple and reliable assay that can be used to evaluate the role of homocysteine in the management of heart disease and can eventually be used for routine clinical testing in doctor's offices. PROPOSED COMMERCIAL APPLICATIONS: As the outcome from this research, we will develop two marketable devices for the rapid determination of homocysteine in plasma. The first will be a hand held portable analyzer suitable for use in the clinic or hospital. The second device, automated high throughput analyzer, will consist of a multichannel device compatible with existing 96-well microtiter plate formats. Automation by means of robotics should increase sample throughput by 8-fold compared to liquid chromatography based methods.